The presence of longitudinal fissures in concrete pipes is a main concern when the time comes to determine the condition of the pipes. According to the standards of the industry, the width of the crack has to be correctly determined in order to classify the defect.
In the art, several tools particularly adapted to provide images of the internal surface of a pipe have been proposed and are currently used. These tools are generally provided with a vehicle adapted to travel in the pipe and an imaging means such as a camera mounted on the vehicle. The vehicle is generally operatively connected to a control unit mounted in the inspection truck proximate the pipe under inspection. An operator inside the truck controls manually the traveling of the vehicle as well as the orientation of the camera to visually inspect the internal surface of the pipe. The grabbed images are generally recorded as a video sequence and the operator can index and comment particularly pertinent images for further review.
The analyst in charge of the observation of the points of interest such as supposed defects, either directly in the truck during the recording of the images or either subsequently to the recording in a central processing center for example, then determines subjectively the severity of the defect.
These inspection systems are well adapted for a coarse visual inspection but can not provide an accurate measure of a defect such as the precise width of the crack at particular point. The visual inspection of the condition of the internal surface of the pipe then depends on the judgment of the operator in charge without relying on an accurate and reliable measure.
Known in the art, there is US patent application published under no. 2003/0016285 which describes an imaging apparatus and method devised to provide accurate measurement of the defects. The described system is however quite complex to implement and not enough heavy-duty, especially for a specific use in small underground sewage pipes.
Other inspection systems using ultrasonic or magnetic devices have also been proposed. These systems do not however provide accurate and reliable measures of the defects.
Therefore, there is a need for an improved system for inspecting the interior surface of a pipeline that would provide accurate and reliable measures of the defects.
The pipelines that generally require a visual inspection for checking their integrity are often underground pipelines. Moreover, these pipes can be of a quite small diameter, as small as eight inches for example. It would therefore be even more desirable to provide an inspection system particularly adapted for inspection of pipes of reduced diameter.